Potential-indicator



(No Model.) 2 SheetsSheet 1. 13. WESTON.

POTENTIAL INDIGATOE.

No. 444,803. 4 Patented Jan. 18, 1891.

J0 4 n a w lT/VESSES:

. Q 4 I f I ATTORNEY.

(No Model.) 2 Sheets-Sheet 2. E. WESTON.

POTENTIAL INDIGATOR. I No. 444,803. Patented J an. 13, 1 891.

Arm/mgr.

, UNITED STATES it PATENT OFFICE.

EDYVARD \VESTON, OF NElVARK, NEXV JERSEY.

POTENTIAL- INDICATOR.

SPECIFICATION forming part of Letters Patent No. 444,803, dated January13, 1891. Application filed ll'nne 5,1890. Serial No. 354,307. (Nomodel.)

To all whom it may concern:

Be it known that I, EDWARD WESTON, of Newark, Essex county, New Jersey,have in vented a new and useful Improvementin Potential Indicators orVoltmeters, of which the following is a specification.

My invention relates to an instrument for showing variations inpotential of the current maintained ona circuit or for indicating theelectrical pressure of a current in volts.

My invention consists, broadly, in an elec trical measuring-instrumentembodying two coils connected in circuit and having their longitudinalaxes in prolongation, one of said coils being both rotary on its axisand movable with reference to the other coil, near which it is placed ininductive proximity, and a means for indicating the extent of retarymovement of said movable coil; also, in an electricalmeasuring-instrument having a translucent scale-plate, and, also, in thevarious instrumentalities and combinations, as hereinafter described,and more particularly set forth in the claims.

In the accompanying drawings, Figure 1 is a vertical section of theinstrument. Fig. 2 is a horizontal section on the line X X of Fig. 1.Fig. 3 is a vertical section of a modification of the apparatus, inwhich the dial or scale is disposed vertically and an incandescent lampis arranged to illuminate the scale marking.

Similar numbers of reference indicate like parts.

Referring first to the form shown in Figs. 1 and 2, 1 is a circular caseforming the base or standard of the instrument, within which is arrangedthe horizontal segmental scaleplate 2. This plate is visible through anopening 3 and cover 4, which opening maybe closed with glass. Supportedon the cover 4 is a cylindrical case 5, provided with a head 6. Securedto this head 6 by the hollow screwbolt 7 is a core 8. Within the case 5and secured to the inner periphery thereof at its lower portion, andresting also on the cover 4, is a ring 9. The ring 9, case 5,cover 6,and core 8 constitute a magnet, in which the ring 9 and core 8 are thepole-pieces. Between the ring 9 and the core 8 there is a narrow annularinterval in which an intense magnetic field is produced. Surrounding thecore 8 within the ring 9 is a spool or bobbin 10 of non-magneticmaterial, which carries a coil 11 of insulated wire. In the intervalbetween the core 8 and ring 9 is disposed a ring 12, of brass or othernon-magnetic material, closed "at its lower side by a diaphragm 13.Extending through the core Sis an axial opening, in which is disposed aspiral spring 14. This spring is connected at its upper end to athreaded rod 15, which passes through a flanged sleeve 16, supported inthe hollow bolt 7 and receives on its threaded end above said sleeve anut 17. The lower end of the spring is connected to a short rod 18,which is fastened to a pin 19, secured at the center of the diaphragm13.

In the lower portion of the opening extending through the core 8 isdisposed a flanged sleeve 20. In said sleeve are two transversepartitions or guides 21 and 22, which may carry jewels, through whichjewels the rod 18 passes. It will be seen, therefore, that the ring 12is thus suspended by the spring 14, and that because of the reception ofthe rod 18 in the jewels in the transverc partitions 21 and 22transverse motion to the suspension device is prevented. On the unwhichis suspended an index-needle 23, the extremity of which extends over thescale 2 and is visible through the opening 3. Extending from the underside of the needle 23, below its point of suspension, is a spring 24, bymeans of which the needle is held in a horizontal position. Surroundingthe ring 12 is a coil of insulated wire, which is connected in serieswith the coil 11. The operation of the instrument is as follows: hen acurrent the potential of which is to be measured is passed through thecoil 11 and also the coil 25, its effect, in accordance with well-knownsupportin g-rin g 12, to be movedlongitudinally upward or downward) inthe space between the core 8 and ring 9 but by reason of the spring 14the ring 12 is also caused to rotate,

The extent of rotation of the coil is proportional to and hence measuresits movement, and this movement has arelation to the magnetic force dueto the difference of potential der side of the diaphragm 13 is a pinfrom laws, is to cause the coil 25, and hence its the rod 18 thenturningin itsjewel-bearings.

between the terminals at which the current enters and leaves theinstrument. As the rotary movement of the ring 12 is transmitted to theneedle 23 it is obvious that the movement of this needle over the scale2, which is suitably marked in volts, will show the said difference ofpotential on the scale.

Referring now to the modification shown in Fig. 3, the lower case orstandard of the instrument is here enlarged and the vertical case 5 isset for some distance down into it. The central opening in the coil 8does not extend entirely through the core. The rod 18, entering saidopening and passing, as before, through the jeweled bearings 21 22,terminates in said opening, and hence acts simply as a guide-rod. sideof the diaphragm 13 is pivoted alink 26, the lower extremity of which ispivoted to a bell-crank lever 27, which in turn is pivoted to a fulcrum28 on the bottom of the case. To the end of the vertical arm of thebellcrank lever 27 is pivoted a forked piece 29, to which is secured oneend of the spiral spring 14. The other end of the spiral spring isfastened to a short threaded rod 29, which is received in the collar 30.Another spiral spring 14* is provided with a threaded rod 31, whichenters the collar 30. The other end of the spring 14* is fastened to athreaded bolt 32, which passes through the side of the case 1, andreceives on the outside of said case a nut 33. The springs 14 and 14*together correspond to the spring 14, (shown in the form of instrumentillustrated in Fig. 1.) Supported on the collar 30 and extendingvertically upward is the needle 34, which is counterweighted at 35. Inthe cover 4 of the case there is an opening through which the needleextends, and above this opening there is a circular frame 35, in Whichare set two plates of glass 36 and 37. On one of these plates of glass37 is inscribed the scale marking, and this plate ofglass is ground ormade partly translucent. Between the case 35 and the case 5 and restingon the cover 4 of the instrument is an incandescent electric lamp 36.The coil 11 and the coil 25 are connected in series, as before. The lamp36 is connected with any independent source of electricity. Theoperation of this formof instrument is as follows: When the current thepotential of which is to be measured is passed through the coils 11 and25, the ring 12, as before, is moved upward or downward, and its motionis transmitted through the link 26 and bell-crank lever27 to the springs14 14*. These springs then, by reason of their construction, rotate,thus rotating the sleeve 30, and so causing the needle '34 to move infront of the scale. Theprinciple of the apparatus is the same as thatalready described in connection with Figs. 1 and 2, the extent ofmovement of the coil having a relation to the magnetic force due to thedifference of potential between the terminals of the instrument, andthis difference of potential being shown by the extent of movement ofthe needle over the scale.

To the center of the lower It will be obvious that in Fig. 1 theposition of the ring 12 may be adjusted by means of the nut 17, and thatin the form shown in Fig. 3 the same result may be accomplished byadjusting the nut 33.

I claim 1. In an electrical measuring-instrument, two coils having theirlongitudinal axes in prolongation, one of said coils being supported soas to be rotary on its axis, and also movable with reference to theother coil and in inductive proximity thereto, and means for indicatingthe extent of rotary movement of said movable coil, said coils beingconnected in circuit.

2. In an electrical measuririg-instrument, two coils having theirlongitudinal axes in prolongation, one of said coils being rotary on itsaxis and movable with reference to the other coil and in inductiveproximity thereto, and meansforinitially adjusting one coil withreference to the other, said coils being connected in circuit.

3. In an electrical measuring-instrument, a fixed coil and a movablecoil having their longitudinal axes in prolongation and placed ininductive proximity, the said movable coil being rotary on its axis andconnected in circuit with said fixed coil, and means for initiallyadjusting the movable coil with reference to the fixed coil.

4. In an electrical measin'inginstrument, two coils having theirlongitudinal axes in prolongation, one of said coils being movable withreference to the other coil, connected in circuit therewith, and ininductive proximity thereto, an elastic support for said movable coil,and a means of indicating the extent of movement of said movable coil.

5. In an electrical measuring-instrument, two coils having theirlongitudinal axes in prolongation, one of said coils being movable withreference to the other coil and electrically connected in circuittherewith and in inductive proximity thereto, the said movable coilbeing supported between opposed springs extending from saidcoil toabutment.

6. In an electrical measuring-instrument, two coils having theirlongitudinal axes in prolongation, one of said coils being movable withreference to the other coil, connected in circuit therewith, and ininductive proximity thereto, means for guiding the movement of saidmovable coil in the direction of its longitudinal axis, and means forindicating the extent of movement of said movable coil.

7. In an electrical measuring-instrument, an electro-magn et, a coilsurrounding the core thereof and free to move in the direction of theaxis of said core, aspiral springconnected to said coil, and anindex-needle vibrated by said spring, the said magnet and coil being incircuit and the said spring rotating by its own elasticity during themovement of said coil and so vibrating said needle.

8. In an electrical measuring-instrument, an electro-magnet having onepole surrounding the other, a coil supported and free to move in anaxial direction in the space between said poles, a means of causing saidcoil while so moving to rotate on its axis, and a means of indicatingthe extent of rotary motion of said coil, the said coil and magnet beingconnected in circuit.

9. In an electrical ineasuring-instrument, an electro-magnet, a hollowcore, a coil surrounding said core, free to move in the direction of theaxis thereof, and a spiral spring within said core and extending betweensaid coil and a fixed abutment, the said coil and magnet being connectedin circuit.

10. In an electrical measuring-instrument, an electro-magnet, a hollowcore, a coil surrounding said core and free to move in the direction ofthe axis thereof, and a suspension device for said coil extendingthrough said core, the said magnet and coil being con nected in circuit.

11. In an electrical ineasuring-instruinent, an electro-magnet, a hollowcore, a coil surrounding said core, free to move in the direction of theaxis thereof, and two opposed springs extending from said coil toabutments, one of said springs being within said core, the said magnetand coil being connect ed in circuit.

12. In an electrical measuring-instrument, an electro-magnet, a movablecoil surrounding the core of said magnet and free to move in thedirection of the longitudinal axis thereof, and a guide-rod connected tosaid coil, moving in fixed bearings, and preventing lateral movement ofsaid coil.

13. In an electrical measuring-instrument, an electro-magnet having anaperture or recess Within its core, a movable coil surrounding the coreof said magnet and free to move in the longitudinal axis thereof, and aguiderod connected to said coil, extending into said recess and througha fixed bearing therein.

14. In an electrical measuring-instrument, an electro-magnet having thehollow vertical core or pole-piece 8 and the ring pole-piece 9,surrounding the end of said core, the coil. 25, suspended in the annularinterval between said ring 9 and core 8, the suspending-spring 14,threaded rod 15, connected to said spring 14, and nut 17. r

15. In an electrical 1neasuring-instrurnent, a tubular electro-magnethaving its coil Within its inclosing-tube, a core within said coil, andan annular pole-piece also within said tube and surrounding theprotruding end of said core, in combination with a coil suspended in theannular space between said pole-pieces and free to move in the directionof the longitudinal axis of said magnet.

16. In an electrical measuring-instrument, an electro-magnet having thehollow core '8 and ring 9, the suspended ring 12 and coil 25 therein,the spiral suspension-spring 14 for said ring 12, the guide-rod l8 andbearings therefor, and the needle 23, connected to said core.

17. In an electrical measuring-instrument, the standard or case 1, case5 thereon, and inclosing an electro-magnet having the core 8 and ring 9,the suspended ring 12 and coil 25 thereon, the needle 23, connected tosaid coil, and the scale-plate 2.

EDWARD IVESTON.

Witnesses:

R. C. FESSENDEN, M. Boson.

